did any one dscover the number of stars in one galaxy?

Answer 1

The best estimate for the Milky Way is 300 billion stars

This might also interest you:

THE DRAKE EQUATION

Estimating the Number of Advanced Civilizations in the Milky Way


In order to estimate the number of advanced civilizations in the Milky Way Galaxy a number of factors need to be combined. The factors, layed out by famed astronomer Frank Drake, have come to be known as the Drake Equation. His equation written out looks like:


N = N* x fs x Np x fe x fl x fi x (L/LMW)


Which breaks down in meaning as:


N = number of communicating civilizations in our galaxy now
N* = number of stars in the galaxy
fs = fraction of sunlike stars
Np = average number of planets per star
fe = fraction of planets suitable for life
fl = fraction of planets where life actually develops
fi = fraction of planets where intelligent civilizations arise
L = lifetime of civilization with ability to communicate
LMW = lifetime of the Milky Way Galaxy


The number of stars in the galaxy is believed to be about 300 billion (300 x 109), therefore N* = 3 x 1011. The number of sunlike stars (i.e. those that last for about 5 billion years so that life can evolve) is almost half of all stars, so to be conservative we take fs = 0.3. Our own modest solar system has nine planets, so we take Np = 10. Again, if we look at our own solar system, we find one planet (Earth) eminently suitable for life and another (Mars) very close to being suitable. If we assume that one planetary system in every four has a planet suitable for life, and if planetary systems have, on average, 10 planets, then one planet in every 40 should have conditions suitable for life, so fe = 0.025. The fraction of planets with suitable conditions for life, and on which life actually develops, is close to unity, but to be conservative we take fl = 0.5. Likewise, the fraction of planets where intelligent civilizations arise is near to unity as well, so we take fi = 0.75.

The final factor in the equation involves the lifetime of intelligent civilizations and the lifetime of the Milky Way galaxy. The lifetime of the galaxy is believed to be about 10 billion years (1010 years), however estimating the lifetime of a communicating civilization is more difficult. The only example we have is our own civilization, which has achieved the ability for interstellar communication in only the last generation or two. But the real question is how long will we last as a civilization? This question is difficult to answer. If we are very pessimistic, we might put L at a few decades; if we are very optimistic, we might measure it on a geological timescale. We can imagine two extreme cases: a technical society that destroys itself soon after reaching the communicative phase (i.e. L<102 years) and a technical society that learns to live with itself soon after reaching the communicative phase; if the society gets past L=102 years, it is unlikely to destroy itself from then on and its lifetime can be measured on a stellar evolutionary scale (i.e. L>>108 years).

This gives N = (3x1011) x (0.3) x (10) x (0.025) x (0.5) x (0.75) x (L/1010)

N = 0.843 L

Given the uncertainty in the various factors in this equation, we can approximate by saying that N = L.

The number of civilizations in our galaxy with the ability to communicate is equal to the lifetime of such civilizations.

So, depending on the value of L, N can range from about 100 to several billion. Most likely, an intermediate value is closer to the truth, so most scientists take N = 106. Thus, there may be a million or so civilizations within our own galaxy with whom we might communicate.

This number refers to the Milky Way Galaxy only. The universe contains at least as many galaxies as there are stars in the Milky Way. The reason for the restriction to the Milky Way is because intragalactic communication seems far easier than extragalactic communication. The nearest star in our galaxy would require several years for a round-trip message, while the farthest stars require tens of thousands of years. In contrast, to exchange a message with a civilization in the Andromeda galaxy would require about 4 million years, while further galaxies would require several billion years (by which time we might well be extinct). So chances for a real conversation is much better if we limit the equation to only the Milky Way galaxy.

http://www.angelfire.com/indie/anna_jones1/drake.html




You can also talk to an astrophysicist at NASA:
http://imagine.gsfc.nasa.gov/docs/ask_astro/stars.html

Answer 2

This pertains to our own Milky Way Galaxy.
People have studied the mass distribution of stars in the galaxy. Further, one also knows the amount of light put out by each type of star. So, by measuring the total amount of light in the galaxy (called luminosity), and knowing the mass, one can estimate the number of stars that are there in the galaxy. So, even though we cannot actually count the number of stars in the galaxy, we can estimate the number of stars in the galaxy as roughly 100 billion (100,000,000,000). It turns out that there are many more stars with mass less than the mass of the Sun than with mass more than the mass of the Sun. So, it all works out right.

The number of stars in the Universe can be estimated by multiplying the number of stars in the Milky Way by the number of galaxies in the Universe. This is a very inexact method but gives us a rough idea.

Answer 3

"large" as in volume, or as in mass? For volume, greatest to smallest: Galaxy cluster, spiral galaxy, globular cluster, nebula, wide action picture star, the solar, Jupiter, white dwarf, black hollow, neutron action picture star. Addendum: Blue Jean makes a valid element in regards to the dimensions of black holes. There are *theoretical* black holes that are very, very tiny. There also are the "supermassive black holes" on the centers of galaxies, which could be larger than the biggest action picture star. the common black hollow, besides the undeniable fact that, will be on the order of a pair dozen miles: larger than a neutron action picture star, yet smaller than a white dwarf (that's quite a few thousand miles in diameter).

Answer 4

nope... we can since we cant see them all. We cant count the number of stars in our own galaxy (the milky way) because the closer stars are in the way of the further stars. As for the other galaxies... they are so far away that it is a blur and blends together.

Answer 5

they can only estimate how many stars are in a galaxy. This is done by calculating its size, luminosity, and distance from earth. And finally by computing how many "sun like" stars must be present for an galaxy of its size to appear as luminous as it is and from far away as it is.

Answer 6

Kind of like the human population, stars are "dying" and being "born" all the time so no one could ever give an exact number of how many there are. How about "infinite?" Does that work for ya?

Answer 7

yes, i did. thanks for asking!